The invention also relates to a method of operating such an ophthalmoscope simulator.
A simulator for simulating the manual manipulation of a direct ophthalmoscope is already known, from the journal article “Ophthalmoscopic examination training using virtual reality”, of D. Lee et al. (1999 Virtual Reality, 4, 184-191, pub. Springer Verlag London Ltd.). The simulation system is comprised of a 3D mouse whereby the observer can move a virtual cone of light of a simulated direct ophthalmoscope relative to a patient head displayed on a display screen. Alternatively, 3D goggles or a head-mounted display are/is provided by means of which the patient head and a cone of light which can be produced on the patient head by an ophthalmoscope, as well as a retina, are displayable to the observer. The display is tracked via a position recognition system, so that either the relative position between the mouse (the ophthalmoscope light cone) and the display screen or the visualized patient head, or the absolute position of the head-mounted display, is displayable to the observer. The virtual scene in this case is completely rendered on the display, without additional frames of reference and without additional hand-held sensors.
The priority document DE 10 2008 027832 A1 incorporates parts of the concept of this reference, but goes beyond that disclosure. The determination of the relative position between the mouse and the head-held display is not included [in said reference]. Therefore, for the purpose of improving upon the intuitive manipulation, the use of an ophthalmoscope is proposed (p. 190 Col. 1 Para. 2). Alternatively, it is proposed that all hand-held sensors (thus the mouse or an ophthalmoscope) be eliminated, and an HMD [(head-mounted display)] be employed which will completely render the scene without other frames of reference (p. 190 Col. 1 Paras. 3-4).
US 2005/0203367 A1 describes an interactive instrument for operating a representation system for CT data, wherein an image component is inserted in the image of a real scene. The real image is that of the head of a patient who is to undergo surgery. Via the described system comprised of the HMD, a pen, and a computer, the CT data made available are superposed over a 3D representation of the real image. The observer thus sees both the real image and the virtual CT data. The pen and the HMD are tracked, so that by means of the pen one can operate an also displayable interactive switching surface for controlling the representation of the CT data. The spatial arrangement of the CT data visualization is determined in relation to six points located on the fixed patient head. The points must be entered by the user by means of the tracked pen, in order to determine the positions of said points. For this purpose the sequence of positions and the actual individual positions of the said points on the patient head must be known. The patient head itself must be registered. The said points serve as a fixed “anchor” for the simulation of the CT data. In the event that the patient head is moved, this will cause loss of the necessary spatial correlation between the CT data and the patient head.